Sampha is the producer people go to when they want to exorcise the ghosts in their machines. The London singer’s pleading voice carries the emotive punch in his own melancholy R&B/pop catalog, and when he’s writing for other artists—whether it’s a lovestruck Jessie Ware or a bullish Kanye West—he cocoons their vocals in an alien blend of warm, chirruping beats and a widescreen wash of immersive electronics.